Membrane process for making enhanced flavor fluids

ABSTRACT

A process using a hydrophobic membrane separation process for making an enhanced flavor fluid, particularly a low-alcohol brew, having improved flavor is disclosed.

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/999,127, filed Dec. 29, 1997, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved membrane separation processfor making enhanced flavor fluids, and particularly, enhanced flavorlow-alcohol brews.

2. Related Background Art

There is potentially a very large and profitable market for non-alcoholbeer beverages, or non-alcohol brews. Most states define "beer" or"wine", as containing one-half of one percent or more of alcohol byvolume. Accordingly, to qualify for the designation as "non-alcohol",the beverage must have an alcohol content of less than 0.5% by volume.Because of the very low alcohol content, "non-alcohol", beverages arenot subject to an alcohol tax, yet can be sold at prices comparable tothat of regular beers that have ethanol concentrations of about 3.0% to5.0% by volume. Despite the potential growth market, current non-alcoholbrews have not become popular because they lack the full flavor ofregular beers.

The chemical composition of the flavor components of any given type ofbeer is very complex, and may include many chemical compounds.Sometimes, important flavor components are present in only traceamounts. However, the major flavor components, that is thosecontributing to the aroma and/or taste of beer, include alcohols andesters. Regular beers contain about 4% ethanol, by volume, and lowerlevels of higher alcohols, such as propanol and isobutyl alcohol. Themajor flavor components are esters, such as ethyl acetate, amyl acetate,phenyl acetate and the like.

Evaporation and dialysis are processes currently used to preparenon-alcohol brews. Both of these processes operate by removing theundesirable alcohol, ethanol, from regular beer. Unfortunately forconsumers, these processes also remove key flavor components during theprocessing and produce non-alcohol brews with poor flavor profiles, thatis taste and aroma profiles. The evaporation process either destroys orcauses the loss of heat-labile and highly volatile flavor components.Dialysis is a membrane separation technique that is generally notselective enough to separate ethanol from the beer without alsoextracting other low molecular weight flavor components. Table 1 liststhe concentration, in parts-per-million (ppm), of selected compoundscomprising the flavor components of commercially available beers:O'Doulls®, a commercially treated non-alcohol brew, Michelob Pale Ale®,a specialty, high-flavor beer, and Budweiser®, a regular, full-flavor,beer, each sold by the Anheuser-Bush Co.,

                                      TABLE 1                                     __________________________________________________________________________                              Old                                                 Compound     Michelob     Milwaukee ®                                     (ppm)  O'Doul's ®                                                                      Pale Ale ®                                                                      Budweiser ®                                                                      NA     Sharps ®                                                                       Coors ® NA                          __________________________________________________________________________    ethyl acetate                                                                        0.7   44.0  23.0   --     --   5.9                                     isoamyl acetate                                                                      0.1   3.2   2.1    --     --   --                                      amyl alcohol                                                                         8.6   78.0  71.0   7.8    4.6  5.0                                     isobutyl                                                                             1.4   34.0  10.0   2.1    2.05 1.9                                     alcohol                                                                       propanol                                                                             1.3   38.0  14.0   1.3    1.1  16.3                                    ethanol*                                                                             0.3   5.2   5.1    0.4    0.36 0.48                                    __________________________________________________________________________     *Ethanol concentration is % by volume                                         NA  Nonalcohol brew                                                      

Inc., St. Louis, Mo., and non-alcohol brews Old Milwaukee®, sold by theStroh Brewery Company, Detroit, Michigan, Sharps®, sold by MillerBrewing Company, Milwaukee, Wisconsin, and Coors®, sold by Coors BrewingCompany, Golden, Colo. The non-alcohol brews lack, or contain very lowconcentrations of important beer flavor components, as compared to ahigh-flavor or full-flavor beer.

Membranes may be used to transport solubilized substances from aconcentrated solution, often called a "feed" solution, through themembrane, to a fluid containing little or none of the substances. Thisfluid is often referred to as a "pick-up" fluid or permeate, becausethis fluid picks up the components from the feed solution by permeationthrough the membrane. The membranes may be used to selectively transportthese substances from a feed solution to a pick-up fluid based ondifferences between the rate of transport of different substances acrossthe membrane.

Many different types of membrane separation systems are well known inthe art and are described in Membrane Separation Systems--A Research andDevelopment Needs Assessment, Vol. II, Chapt. 1, by R. W. Baker,prepared by the U.S. Department of Energy, Final Report: April, 1990.

Improved ethanol extraction membranes have been developed. For example,Maston, U.S. Pat. No. 4,816,407, discloses use of a semi-permeablemembrane for extracting ethanol from an alcohol-containing composition.However, it would be useful to develop flavor component extractingprocesses to provide a flavor extract that could be used to reconstituteor enhance the flavor profile of the present non-alcohol brews.

The process of pervaporation has been applied to the extraction of aromacomponents in wine. D. Beaumelle, et al., Journal of Food Engineering,16 (1992) 293-307. Pervaporation is a separation process used tofractionate liquid mixtures to transport organic aroma componentsthrough a membrane to a permeate followed by evaporation of the permeateand the recovery of the aroma faction. The recovered aroma fraction maybe used to restore the flavor of non-alcohol wine. A major disadvantageof this process is the required evaporation of the permeate. Theconcentration of highly volatile aroma components in the aroma fractionmay be reduced as a result of this treatment, thereby reducing thequality of the "aroma" added back to the non-alcohol wine.

Accordingly, it would be advantageous to develop a selective separationprocess that could provide enhanced separation between flavor componentsand alcohol and produce enhanced flavor fluids, particularly low-alcoholbrews, having the complete spectrum of the taste and aroma componentsextracted in the separation process.

SUMMARY OF THE INVENTION

One aspect of this invention is a process for making an enhanced flavorfluid, particularly a low-alcohol brew, having an improved flavorprofile, wherein a feed solution, containing the desired flavorcomponents, such as a regular or specialty beer, is contacted with, orexposed to, a pick-up fluid, containing little or none of the desiredflavor components, such as a low-alcohol brew, through a hydrophobicmembrane. Flavor components are extracted from the feed solution intothe pick-up fluid via the hydrophobic membrane to provide an enhancedflavor fluid having increased concentrations of flavor components.Hydrophobic membranes, useful in the process of this invention, includesolid hydrophobic membranes and hydrophobic polymeric liquid membranesthat can selectively transport flavor components of beer or other highlyflavored fluids, without transporting significant amounts (reduced theconcentration) of undesired components, e.g., ethanol. Particularlypreferred hydrophobic polymeric liquid membranes include liquidpolyglycol membranes. These membranes advantageously demonstrate highselectivity for the transport of flavor components over transport ofethanol and may be used to produce low-alcohol brews with enhancedflavor characteristics.

Another aspect of this invention is a process for making an enhancedflavor fluid, particularly a low-alcohol brew, having an improved flavorprofile wherein a feed solution, containing the undesired flavorcomponents, such as a commercially prepared low-alcohol brew, iscontacted with, or exposed to, a pick-up fluid or gaseous stream,containing little or none of the undesired flavor components, through ahydrophobic membrane. Undesired flavor components are extracted from thefeed solution into the pick-up fluid via the hydrophobic membrane toprovide an enhanced flavor fluid having decreased concentrations ofundesired flavor components.

Yet another aspect of this invention is directed to a recycle processfor making an enhanced flavor fluid, wherein a first feed solution isextracted with a pick-up fluid to form an enhanced flavor fluid and anextracted feed solution. Optionally, this extracted solution may betreated to remove any undesired components. The resulting treatedextracted feed solution may be used as a second pick-up fluid to extractflavor components from a second batch of feed solution to produceadditional enhanced flavor pick-up fluid and additional extracted feedsolution. Repetition of this cycle provides a continuous source ofextracted feed solution and enhanced flavor pick-up fluid.

DETAILED DESCRIPTION OF THE INVENTION

According to the separation process of this invention, sufficientconcentrations of flavor components, that is components contributing toaroma and/or taste, may selectively pass through a hydrophobic membranefrom a feed solution, containing the desired flavor components, into apick-up fluid, containing little or none of the desired flavorcomponents. This process provides an enhanced flavor fluid havingincreased concentrations of flavor components. Specifically, thisprocess may be used to provide an enhanced flavor low-alcohol brewhaving increased concentrations of beer flavor components and an alcoholconcentration of less than 3.0%, and preferably less than 0.5% byvolume. According to the process of the present invention, thehydrophobic membrane is positioned between the feed solution and thepick-up fluid. The feed solution, containing the desired flavorcomponents, such as a regular beer or a specialty beer, contacts oneside of the membrane and the pick-up fluid, containing little or none ofthe desired flavor components, such as a low-alcohol brew, contacts theother side of the membrane to accept the target components as theypermeate through the hydrophobic membrane.

In another embodiment of this invention, sufficient amounts ofundesirable flavor components may selectively pass through a hydrophobicmembrane from a feed solution, containing an undesirable flavorcomponent, into a pick-up fluid, containing little or none of theundesirable component. This process provides an enhanced flavor fluidhaving decreased concentrations of undesirable flavor components.Specifically, this process may be used to provide an enhanced flavorlow-alcohol brew having decreased concentrations of "beanie" or"vegetative" off-flavors, with retained concentrations of desired flavorcomponents and an alcohol concentration of less than 3.0%, andpreferably less than 0.5% by volume. According to the process of thisinvention, a flavor fluid, such as a low-alcohol brew having undesirableflavor notes, contacts one side of a hydrophobic membrane and a pick-upfluid, composed of another fluid or a gaseous stream contacts the otherside of the membrane to accept the target undesirable flavor componentsas they permeate through the hydrophobic membrane. Accordingly, anenhanced flavor fluid may be prepared by either increasing theconcentration of desired flavor components or decreasing theconcentration of undesired flavor components in a flavor fluid byappropriate selection of the feed solution and pick-up fluid.

Using a plate-and-frame configuration, a feed solution is exposed to orcontacted with the pick-up fluid via a flat sheet membrane. In thisconfiguration, the membrane sheet is located within a liquid tighthousing, or cell, that divides the interior of the housing into at leasttwo chambers, or compartments, i.e., a feed solution compartment and apick-up fluid compartment. The housing is provided with inlet and outletports or manifolds which permit introduction and removal of the feedsolution and the pick-up fluid, and is typically provided with amechanism for stirring or agitating the liquids.

Using another configuration, exposure or contact between the feedsolution and pick-up fluid may be accomplished by circulating the feedsolution through the lumens of hollow fibers having microporous wallssupported in a housing, the fiber walls constituting the hydrophobicmembrane, and circulating the pick-up fluid over the outside of thefibers, also referred to as the shell side. Alternatively, the pick-upfluid may be circulated through the lumens and the feed solutioncirculated over the outside of the fibers (the shell side). The choiceof the placement of the feed and pick-up fluids may be dependent uponoperator preference. This use of the hollow fiber configuration providesvery high surface area contact between the feed solution and pick-upfluid. The housing used with this configuration is also provided withinlet and outlet ports or manifolds which permit introduction andremoval of the feed solution and the pick-up fluid.

Hydrophobic membranes useful in the present invention include bothhydrophobic solid membranes, i.e. dense films, or supported hydrophobicsolid membranes, and supported hydrophobic liquid membranes. As usedherein, the term "supported membrane" refers to a non- rigidmembrane-forming compound or composition that is supported or dispersedwithin a solid structure, typically a solid microporous material, i.e.,a microporous support. The term "hydrophobic" describes a material thatis substantially water insoluble and water immiscible. By "waterinsoluble" it is meant that the membrane is so sparingly soluble in anaqueous solution, with which it is in contact during use, that itremains in contact with the microporous support for an extended timewithout dissolving into the aqueous feed or pick-up solutions. In termsof the present invention and depending on the particular application, anextended time period can be from several hours to several weeks.Preferably, a hydrophobic material is soluble in an aqueous solution inan amount of less than about 50 ppm, more preferably less than about 30ppm and most preferably less than about 10 ppm. The water solubility inthe hydrophobic membranes useful in this invention should be less thanabout 10%, preferably less than about 5%, and generally it should beabout 3% or lower.

Microporous supports useful for supporting the solid or liquid membranesin the present invention and their methods of preparation are well knownin the art. Exemplary microporous supports may be found in U.S. Pat. No.3,426,754; U.S. Pat. No. 3,801,404; U.S. Pat. No. 3,802,444; U.S. Pat.No. 3,839,516; U.S. Pat. No. 3,843,761; U.S. Pat. No. 3,843,762; U.S.Pat. No. 3,920,785; U.S. Pat. No. 4,055,696; U.S. Pat. No. 4,255,376;U.S. Pat. No. 4,257,997; U.S. Pat. No. 4,359,510; U.S. Pat. No.4,405,688 and U.S. Pat. No. 4,438,185, the disclosures of which arehereby incorporated by reference. Generally, a hydrophobic microporoussupport is a material that is not spontaneously wet by water, having anopen-celled, inter-connected structure. The microporous support shouldoptionally be composed of material that is compatible with thehydrophobic solid or liquid polymer used therewith. Exemplarymicroporous support materials include polyolefins, polysulfones,polytetrafluoroethylenes, polycarbonates, polyether ketones,polystyrenes, and the like. The pore size of the support should be thesmallest size to efficiently transport the target components, and thesupport should have the highest porosity and smallest thicknessconsistent with adequate mechanical integrity. The support may be in anyconfiguration, such as a flat sheet or a spiral wound or a hollow fiber.

Microporous membranes meeting these descriptions are commerciallyavailable from several sources and are well known to those skilled inthis art. In such materials, the micropores are interconnected throughpathways which extend from one membrane surface or surface region to theother. The pores of commercially available microporous material fallpredominantly in the range of about 0.02 to about 2 microns in effectivediameter, although the size of individual pores often vary considerablyfrom the noted average pore size. Pores as small as 0.01 micron and aslarge as 10 microns are not unusual, and a specific pore size is notcritical. For example, microporous materials having an average pore sizeof about 0.1 micron provide stable liquid membranes using polypropyleneglycol with a molecular weight of about 4000. Typically, commercialmembrane support thicknesses range between 10 and 200 microns.

As noted above, the porosity must be sufficient to provide an opennetwork through the support (open pore structure). Typically,commercially available microporous membrane supports will have aporosity of from about 30% to about 80%, with a more usual porosity foran isotropic membrane like the Celgard® membrane (see infra) being inthe range of about 40% to about 50%. Porosity is defined as thefractional volume (expressed as a percent) of the membrane that is openrather than substrate material. Porosity can be assessed in analternative fashion by reference to the material's bulk density.Suitable microporous materials will have a bulk density lower than thebulk density of the same polymeric material having no cellularstructure. Bulk density refers to the weight of the material per unit ofits gross volume, where gross volume is the volume of fluid displaced,where the fluid such as mercury, exhibits a surface tension thatprevents it from flowing into the micropores of the material. Seemercury volumenometer method in Kirk-Othmer Encyclopedia of ChemicalTechnology, Vol. 4, page 892 (1949).

While the porosity of the support often times will be uniform across itscross-section, in an alternative embodiment, the hydrophobic microporoussupport may have an asymmetric porosity. For example, the surface regionof the support may have smaller pores and/or a lower porosity than themajor matrix region, whose more open porosity facilitates transport ofthe target component. Such a construction may provide higher transferrates relative to use of uniform porosity membrane supports. Anasymmetric polysulfone membrane meeting such a construction is disclosedin U.S. Pat. No. 5,030,672, the disclosure of which is incorporated byreference.

Preferred microporous supports useful in the present invention includehydrophobic microporous films, such as the CELGARD® and Liqui-Cel®Extraflow polypropylene membrane materials available from HoechstCelanese Separations Products Division, Hoechst Celanese Corporations,South Point, N.C., perfluorocarbon polymers, particularly of the typedesignated Gortex®, a trademark of W. L. Gore & Associates, Inc.,Newark, Delaware, and polypropylene hollow fibers available from Akzo N.V. under the Accurel™ and Liqui-Cel® label.

Hydrophobic solid membranes useful in the present invention aredescribed in U.S. Pat. No. 5,552,053, the disclosure of which isincorporated herein, by reference and include solid silicone membranessuch as siloxane polymers available from Sigma Chemical Co., St. Louis,Mo., and polydimethylsiloxane elastomer membranes available fromMembrane Products Corp., Salt Lake City, Utah. The hydrophobic solidmembrane may be a continuous film that is strengthened sufficiently bycross-linking to be used alone, supported on a frame or overlaid, and/orcast on a microporous support. Alternatively, the hydrophobic membranesmay reside within the pores of a microporous support. If the solidpolymer is a continuous film itself, it contains no pores. Further, itis understood that if the solid polymer either overlays or is cast onthe microporous support or is within the pores of the microporoussupport, the pores of the support or membrane lead from one surface ofthe support or membrane to the other.

There are a wide variety of known hydrophobic polymeric solids that maybe used in preparing the solid membrane of the present invention. Eithernatural or synthetic hydrophobic, polymeric solids may be used.Representative polymeric solids useful in the present invention arepolyalkylene oxides, particularly polypropylene glycols,polytetramethylene glycols, polyhexamethylene glycols, polyhexamethyleneglycols and polyheptamethylene glycols, polyesters, polyureas,polyurethanes, silicones, and the like. For example, apolydimethylsiloxane membrane is useful to selectively transport higher(C₄ -C₅) alcohol and ester compounds over ethanol. Solid polymers, maybe made into a continuous film or polymerized in or compressed into thepores of a microporous membrane. Such solid polymers are safe to handleand highly resistant to mechanical loss from the hydrophobic microporoussupport.

A supported hydrophobic solid membrane useful in this invention may beprepared, for example, by either forming a thin selective separationfilm on a porous support or filling the pores of a support with apolymerizable compound that may be polymerized in the support, therebyforming the solid membrane.

The supported hydrophobic liquid membranes, useful in the process ofthis invention are composed of a microporous support having a waterinsoluble hydrophobic liquid immobilized within the pores of themicroporous structure. The pores of the microporous membrane supportshould be sized so as to retain the oligomeric and polymeric liquidwithin the pores of the support by capillary action. With a propercombination of pore size and porosity, loading of the liquid oligomer orpolymer into the porous matrix is easily accomplished, but capillaryforces remain sufficiently strong to resist expulsion of the oligomer orpolymer liquid from the support during use of the liquid membrane.

The hydrophobic liquid polymers useful in this invention may be anywater-insoluble, water-immiscible liquids having high affinity fororganic compounds. The liquid polymers useful in the present inventionmay be relatively low molecular weight hydrocarbons, i.e. hexadecane, tohigh molecular weight oligomeric or polymeric liquid compounds.

Exemplary supported polymeric hydrophobic liquid membranes, useful inthe process of this invention, are described in U.S. Pat. No. 5,507,949,the disclosure of which is incorporated herein, by reference. Many ofthe useful hydrophobic liquid oligomers and polymers may be described aspoly(amphiphilic) compounds. The term poly(amphiphilic) compound refersto a class of oligomers or polymers having alternating polar regions andhydrophobic regions. These regions of polarity and hydrophobicitytypically alternate along the oligomer or polymer backbone in such amanner that the molecule has a high density of both polar andhydrophobic moieties. Either natural or synthetic hydrophobic,oligomeric and polymeric liquids may be used to prepare the hydrophobicliquid membrane used in the process of this invention. Exemplaryhydrophobic liquid polymers include polyalkylene oxides, particularlypolypropylene glycols, polybutylene glycols, polytetramethylene glycols,polypentamethylene glycols, polyhexamethylene glycols andpolyheptamethylene glycols, polyesters, polyureas, polyurethanes,silicone oils, paraffin oils (saturated hydrocarbons) functionalizedpolyolefins, and the like. Polyalkylene oxides are particularlypreferred hydrophobic liquid polymers.

Preferred supported hydrophobic liquid membranes, useful in the processof this invention, include polypropylene glycols, polybutylene glycols,hexadecane, dodecane, paraffin oils, silicone oils and the like.Advantageously, selection of a particular hydrophobic liquid membranemay be used to selectively produce enhanced flavor fluids, such aslow-alcohol brews, having different flavor characteristics, wherein theconcentration of different flavor components are selectively increased.For example, polybutylene glycol liquid membranes show very highselectivity for the transport of ester compounds and C₅ alcohols overlower C₂ -C₄ alcohols. In contrast, polypropylene glycol and siliconemembranes show almost equal selectivity for transport of C₄ -C₅ alcoholsand ester compounds. Hexadecane membranes selectively transport amyl andisobutyl alcohols over ethanol and esters, ethyl acetate and isoamylacetate. These membranes may also be useful for removing undesirableflavor components present in low-alcohol brews, such as beanie or bitteroff-flavors, which may be due to the presence of compounds such as2-pentyl pyridine, 2-pentenal, ethyl vinyl ketone, 1-octen-3-ol, and thelike. Although any of the preferred supported membranes described abovemay be useful for removing undesired flavors by the extraction method ofthis invention, it has been found that polybutylene glycol membranes aremore efficient than silicone oil membranes at removing beanie off-notes. Thus, these hydrophobic membranes may be used to producebeverages, and particularly low-alcohol brews, possessing enhanced, yetvaried, flavor characteristics.

The supported liquid polymeric membrane used in this invention may beprepared, for example, by wetting a flat sheet of microporouspolypropylene (Celgard 2500, 45% porosity, 0.75 micron average poresize, 25±2.5 microns thick, manufactured by Hoechst Celanese Corp.,Charlotte, N.C.) with a few drops of a suitable hydrophobic liquidpolymer and spreading the polymer over the surface of the sheet. Excesspolymer may be wiped off the membrane with an absorbent material.Alternatively, the hydrophobic liquid polymer may be immobilized inlumens of hollow fibers by pouring or pumping a polymer, that optionallymay be heated to about 60° C., into the lumen side of a verticallyoriented Liqui-Cel® Extra-Flow Membrane Contactor module (HoechstCelanese Corp., Charlotte, N.C.). The polymer is allowed to flow throughhollow fibers. Excess polymer is collected as it drips out of the coatedlumens. Nitrogen may then be passed through the lumen side to force outthe residual polymer.

In one embodiment of this invention, wherein the enhanced flavor fluidcontains an increased concentration of desired flavor components, thefeed solution is the source of the flavor components. Accordingly, thefeed solution used to prepare an enhanced flavor low-alcohol brew, maybe any full flavor beer containing high concentrations of the desiredflavor components. Full flavor beers include any commercial-graderegular beer, ale, lager or the like, and preferably, any specialtybeer. As used herein, a "regular" beer is a commercial-grade beertypically light in color, containing approximately 5% alcohol by volume,and possessing full beer flavor. "Regular" beers are exemplified bybeers sold under the following brand names: Budweiser®, Miller®, MillerLight®, Pabst Blue Ribbon®, Rolling Rock®, and the like. A wide varietyof regular beers, ales, and lagers are commercially available, eachpossessing common taste and aroma components, but in varyingconcentrations. As used herein, a "specialty" beer is a beer thatpossesses a richer beer flavor than a "regular" beer, i.e., a beer thatcontains higher concentrations of the desirable flavor components. Awide variety of specialty beers are available from large scalecommercial breweries as well as smaller scale micro-breweries, eachpossessing common taste and aroma components, but in varyingconcentrations. The concentrations of flavor components vary not onlyfrom beer to beer, or ale to beer, but may also vary from batch tobatch, depending upon differences in the ingredients used to prepare thebeer as well as variations in the brewing process. For example, theconcentrations of the flavor components in the beer feed solutions usedherein are slightly different from sample to sample. Generally, however,most regular beers will have isobutyl alcohol concentrations in therange of about 10 to about 25 ppm and propanol concentrations in therange of about 10 to about 30 ppm. Specialty beers, however, willtypically contain these components in concentrations that areapproximately 5-20 ppm higher than in regular beers. "Specialty" beersare exemplified by beers sold under the following brand names: MichelobPale Ale®, Red Dog Beer®, Anchor Steams, Samuel Adams®, and the like.

It is understood that each of the regular and specialty beers, asexemplified above, possesses different flavor profiles. Accordingly, useof different beers, or a combination of beers, as the feed beer willproduce different enhanced flavor brews, each having different flavorprofiles. It is considered to be within the ordinary skill of one in theart to select a beer, or combination of beers, to produce an enhancedflavor brew possessing desired flavor characteristics, using the methodof this invention.

In the same embodiment of this invention, wherein the enhanced flavorfluid contains an increased concentration of desired flavor components,the pick-up fluid is a fluid that contains lower concentrations offlavor components than a full flavored feed solution and is a fluid inwhich these components are soluble. Generally, the concentration ratioof the flavor components in the initial feed solution to the flavorcomponents in the initial pick-up fluid is greater than 1:1. Thepreferred pick-up fluid used in this embodiment of the invention is acommercially produced non-alcohol brew, or other low-alcohol brew,lacking or having very low concentrations of beer flavor components.Typically such a low-alcohol brew has been subjected to a treatment thathas reduced the content of the flavor components of the beer. Exemplarytreated brew pick-up fluids include evaporated non- alcohol brew,dialysis-treated non-alcohol brew, and the like.

In another embodiment of this invention, wherein the enhanced flavorfluid contains a decreased concentration of undesired flavor components,the feed solution is the source of the undesired flavor components.Accordingly, the feed solution used to prepare an enhanced flavorlow-alcohol brew, may be any low-alcohol brew, either an enhanced flavorlow-alcohol brew prepared as described above, or may be any commerciallyavailable low-alcohol brews, exemplified above, containing detectableconcentrations of the undesired flavor components. The undesired flavorcomponents may be present only in trace amounts, such that they may notbe detectable by analytical techniques, but may be detectable byolfactory senses (taste or smell of the fluid). Advantageously, themethod of this invention may be used to remove, or substantially remove,such trace amounts of undesired flavor components that adversely effectthe taste profile of the low-alcohol brew to provide low-alcohol brewshaving significantly enhanced flavor. In this embodiment of theinvention, wherein the enhanced flavor fluid contains a decreasedconcentration of undesired flavor components, the pick-up fluid is afluid or gaseous stream that contains none or only a low concentrationof the undesired flavor component(s) and is a fluid or gas into whichthese components may be absorbed. Generally, the concentration ratio ofthe flavor components in the initial feed solution to the flavorcomponents in the initial pick-up fluid is greater than 1:1. Thepreferred pick-up "fluid" used in this embodiment of the invention maybe a fluid or a gas in which the undesirable flavor component may bepreferentially adsorbed or solubilized, compared to the desired flavorcomponents. Exemplary pick-up fluids include water, carbonated water,ethylene glycol, and polyglycols (polyethylene glycol, polypropyleneglycol, polybutylene glycol, and the like), and exemplary pick-up gasesinclude carbon dioxide, nitrogen and the like.

Extraction of the flavor components from any of the above-described feedsolutions may be conducted in a batch mode by exposing a selectedpick-up fluid to a single batch of feed solution. Alternatively,extractions may be conducted in a simulated continuous mode by changingthe feed solution periodically in the cell. Membrane composition,contact time, temperature, and relative flow rates of the feed solutionand pick-up fluid are some of the parameters that may be modified tochange the extraction rate or the selectivity of the extraction orseparation of the flavor components from the feed solution. Accordingly,adjusting these parameters will vary the flavor profile of the resultingenhanced flavor fluids. It is understood that such adjustment is readilyperformed by one of ordinary skill in the art.

Another embodiment of this invention is a recycle process for anenhanced flavor fluid having increased concentrations of desired flavorcomponents, wherein a first batch of a full flavor feed solution,containing desired flavor components, is placed in contact with asurface of a hydrophobic membrane, which membrane is also in contactwith a pick-up fluid containing comparatively lower concentrations ofthese flavor components. Optionally, this pick-up fluid may have beentreated to remove or substantially remove any undesirable components, asdescribed above. The flavor components are extracted from the feedsolution into the pick-up fluid to form an enhanced flavor fluid and anextracted feed solution. This extracted feed solution contains reducedlevels of the flavor components, but may also contain highconcentrations of undesired components. Accordingly, this extracted feedsolution may be treated to remove or substantially remove the undesiredcomponent, thereby forming a treated extracted feed solution. Thissolution may then be recycled and used as the pick-up fluid in anadditional extraction process. Accordingly, a second batch of a fullflavor feed solution containing flavor components may be placed incontact with a surface of a hydrophobic membrane, which membrane is alsoin contact with the second pick-up fluid composed of the treatedextracted feed solution. Extracting the flavor components from thissecond feed solution into the second pick-up fluid (the treatedextracted feed solution) will provide a fluid having the undesiredcomponent removed or substantially removed therefrom but having enhancedflavor and a second batch of an extracted feed solution. Accordingly,this process may be repeated to provide a continuous source of extractedfeed solution and enhanced flavor fluid having an undesired componentremoved or substantially removed therefrom.

Specifically, this recycle method may be used to make enhanced flavorlow-alcohol brew, wherein the extracted feed solution, e.g., the feedbeer that results after contact and extraction with a pick-up fluid, maybe used as the pick-up fluid for a fresh batch of feed solution, e.g.,full flavor or enhanced flavor beer. The extracted feed beer containsreduced levels of flavor components, but still contains a normal, andundesirably high, alcohol content (approximately 4-5% by volume) orundesirable flavor component(s). Accordingly, the extracted beer may besubjected to a treatment, such as evaporation or dialysis, to remove orsubstantially remove the alcohol, and may optionally be used as a feedsolution in a second membrane extraction process to remove orsubstantially remove undesirable flavor component(s) to form a treatedlow-alcohol brew. This treated low-alcohol brew may then be used as thepick-up fluid for another fresh feed solution of full flavor beerproviding additional enhanced flavor low-alcohol brew and extractedbeer. This process may be repeated to thereby provide a continuoussource of extracted beer for conversion to enhanced flavor low-alcoholbrew. The recycling process may be conducted in a batch mode or in acontinuous mode, as described above.

Experimental Procedures

Two sizes of cells were used for the laboratory scale experiments. The"normal" size cell can contain approximately 30 ml of fluid in each cellcompartment. The "10×" size cell can contain approximately 500 ml offluid in one compartment and approximately 230 ml of fluid in theopposing compartment. The feed solution is generally placed in thelarger (500 ml) compartment. Batch mode extractions were conducted byexposing a pick-up fluid to a single batch of feed solution forapproximately 24 hours. Simulated continuous mode extractions wereconducted by changing the batch of feed solution in the cellperiodically, typically at 3 to 8 hour intervals. Theexposure/extraction time of any batch of feed solution may be lengthenedor shortened to obtain a desired concentration of the flavor components.The surface area of the membrane between the compartments and in contactwith the fluids is 8 cm² for the normal size cell and 44.2 cm² for the10× cell. It is understood that the size and/or configuration of thelaboratory extraction cells, used herein, is not intended to limit thesize and/or configuration of the extraction apparatus for large scaleseparations, employing gallons of feed solution. Budweiser®, MichelobLight®, and Michelob Pale Ale®, all commercial grade beers, were used asfeed solutions. Budweiser® is a beer having the alcohol, flavor andcalorie content of a regular U.S. commercial beer. Michelob Light® hassimilar alcohol content but a reduced caloric content. Michelob PaleAle® has normal alcohol content but has higher concentrations of flavorcomponents than typical beers.

The Examples which follow are intended as an illustration of certainpreferred embodiments of the invention, and no limitation of theinvention is implied.

EXAMPLE 1

Hydrophobic liquid membranes, containing the liquid polymerspolypropylene glycol (PPG, Mol. Wt. 4000), polybutylene glycol (PBG,Mol. Wt. 4800) and silicone (polydimethylsiloxane, Mol. Wt. 12500), wereprepared by separately treating flat sheets of Celgard® 2500polypropylene microporous membrane with one of the polymeric liquids.Each liquid hydrocarbon was introduced into the pores of a Celgard® 2500membrane by wetting the sheet with drops of the liquid. Excess liquidwas wiped off with a tissue. The Michelob Light® beer, a beer having thealcohol and flavor components of a regular U.S. commercial beer, butwith reduced calorie content, available from Anheuser-Bush Co., Inc.,St. Louis, Mo., was used as the feed solution. HPLC grade water, wasused as the pick-up fluid. These flavor components were undetectable inthe HPLC grade water. Extractions were conducted at room temperature inbatch mode using flat sheet membranes in normal size cells. Liquids ineach of the cell compartments were magnetically stirred. The extractionswere conducted at room temperature for about 24 hours. Theconcentrations of the representative flavor components, e.g., C₂ to C₅alcohols and esters, ethyl acetate and amyl acetate, in the feedsolution and pick-up fluid were determined by gas chromatographicanalysis using a 25 m×0.53 mm LD CP-Wax 52 fused silica column.(Chrompack, Inc., The Netherlands).

Table 2 shows the ratio of the concentration of the flavor component inthe pick-up fluid to its concentration in the feed after a 24 hourexposure/contact. A value of 1 indicates that equilibrium was reached,i.e., the pick-up and feed contained equal concentrations of acomponent. A low ratio indicates a slow rate of transport of thecomponent across the membrane.

                  TABLE 2                                                         ______________________________________                                        Pick-up/Feed Ratio                                                            Component    PPG*       PBG**   Silicone                                      ______________________________________                                        ethyl acetate                                                                              1.1        1.1     1.1                                           isoamyl acetate                                                                            1.1        1.1     1.1                                           amyl alcohols                                                                              1.0        0.8     1.0                                           isobutyl alcohols                                                                          0.8        0.3     0.7                                           propanol     0.6        0.2     0.5                                           ethanol      0.3        0.1     0.2                                           ______________________________________                                         *PPG  polypropylene glycol                                                    **PBG  polybutylene glycol                                               

The esters, ethyl acetate and isoamyl acetate, permeate through each ofthese membranes, reaching equilibrium concentrations in less than 24 hrsof exposure. Polyglycol and silicone liquid membranes permit amylalcohol and isobutyl alcohol to reach near equilibrium concentrationsafter 24 hour exposure, whereas only low concentrations of ethanol canbe detected. Thus, these hydrophobic membranes can be used toselectively transport high concentrations of flavor components of beerwithout transporting significant concentrations of ethanol.

EXAMPLE 2

Stirred solutions of Michelob Light® beer (feed solution) and HPLC gradewater (pick-up fluid) were contacted through a polybutyleneglycol-4800/Celgard® 2500 liquid membrane, prepared as described above,at room temperature. Using laboratory scale normal size cells, acontinuous mode process was simulated by replacing exposed feed,Michelob Light® beer, with fresh beer at intervals of 6.0, 6.0, 4.8, 8.0and 2.3 hours, for a total exposure time of 27 hours. Table 3 shows thecompositions for the initial Michelob Light® beer and the resultingpick-up fluid, or the enhanced flavor pick-up fluid, after the five feedchanges, noted above. Use of a simulated continuous mode extractionprocess produced a low-alcohol pick-up fluid containing beer flavorcomponents at concentrations nearly 70-90% of a full-flavor beer, yetcontaining less than 10% of the ethanol present in a full-flavor beer.

                  TABLE 3                                                         ______________________________________                                                                  Final Pick-up                                                    Michelob Light ®                                                                       Fluid                                               Component    (feed, ppm)  (Pick-up, ppm)                                      ______________________________________                                        ethyl acetate                                                                              16           13                                                  isoamyl acetate                                                                            1.4          1.2                                                 amyl alcohols                                                                              59           39                                                  isobutyl     8.5          2.7                                                 alcohol                                                                       propanol     13           2                                                   ethanol (vol %)                                                                            3.4          0.3                                                 ______________________________________                                    

EXAMPLE 3

Two extraction cells were prepared having Michelob Light® beer, as thefeed solution, and HPLC grade water, as the pick-up fluid, and contactedthrough a polybutylene glycol-4800/Celgard® 2500 liquid membrane,prepared as described above, for a period of 24 hours. The extractionsfor each cell were independently conducted at temperatures of 21° C. and4° C. Table 4 shows the pick-up/feed ratios of the representativecomponents at 21° C. and 4° C. A value of 1 indicates that equilibriumwas reached.

                  TABLE 4                                                         ______________________________________                                        Pick-up/Feed Ratio                                                            Component         21° C.                                                                         4° C.                                        ______________________________________                                        ethyl acetate     1.1     0.6                                                 isoamyl acetate   1.1     1.3                                                 amyl alcohols     0.8     0.3                                                 isobutyl alcohol  0.3     0.1                                                 propanol          0.2     0.03                                                ethanol           0.1     0.01                                                ______________________________________                                    

The ratio of ethyl acetate to ethanol pick-up/feed ratios increasedsignificantly from 11 at 21° C. to 60 at 4° C. after 24 hour exposure.Accordingly, the use of lower temperatures reduced the rate of transportof components across the membrane and enhanced the separationselectivity between alcohol and ester compounds.

EXAMPLE 4

Extractions were conducted for differing time periods using MichelobLights beer (feed), HPLC grade water (pick-up) and a PBG-4800/CelgardO2500 membrane. As indicated in Table 5, isoamyl acetate, ethyl acetateand amyl alcohol reach equilibrium or near equilibrium concentrationsafter a 5 hour exposure period, whereas only low concentrations ofethanol were extracted by the pick-up fluid.

                  TABLE 5                                                         ______________________________________                                        Pick-up/Feed Ratio                                                            Component     5 Hour Exposure                                                                           21 Hour Exposure                                    ______________________________________                                        ethyl acetate 0.7         1.1                                                 isoamyl acetate                                                                             1.1         1.1                                                 isoamyl alcohols                                                                            0.8         1.0                                                 isobutyl alcohol                                                                            0.3         0.8                                                 propanol      0.2         0.6                                                 ethanol       0.1         0.3                                                 ______________________________________                                    

The length of time the feed solutions and pick-up fluids are exposed, orplaced in contact with the liquid membrane effects the amount of flavorcomponents that are transported from the feed to the pick-up fluid. Useof shorter exposure/contact times reduces the concentration of some ofthe components in the pick-up, but also provides enhanced separationselectivity between alcohol and ester compounds.

EXAMPLE 5

The hydrophobic membrane was prepared by treating a flat sheet ofCelgard® 2500 polypropylene microporous membrane with hexadecane (soldby Burdick and Jackson, Muskegon, Mich.). The liquid hydrocarbon wasintroduced into the pores of the membranes by wetting the sheet withdrops of the liquid. Excess liquid was wiped off with a tissue. Thisprocess was repeated two times. Extractions were conducted at roomtemperature in batch mode using flat sheet membranes in normal sizecells. The feed solution used in this example, was a specialty beer,Michelob Pale Ale®, which has a higher concentration of flavorcomponents than regular beer, i.e., Michelob Light® beer. HPLC gradewater was used as the pick-up fluid. The liquids (approximately 30 ml)in each of the cell compartments were magnetically stirred, andextraction was conducted at room temperature for 20.3 hours.

Table 6 shows the ratio of the concentration of the flavor components inthe final pick-up fluid relative to the concentration of thesecomponents in the final feed solution, after a 24 hour exposure/contact.A value of 1 indicates that equilibrium was reached, i.e., the pick-upand feed contained equal concentrations of a component. A low ratioindicates a slow rate of transport of the component across the membrane.

                  TABLE 7                                                         ______________________________________                                                   Pale    Pale                                                                  Ale ®                                                                             Ale ®  Final Final                                                (Initial                                                                              (Final     Pickup                                                                              Pick-up/                                             Feed,   Feed,      Solution                                                                            Feed                                      Component  pm)     ppm)       (ppm) Ratio                                     ______________________________________                                        ethyl      20.1    15.9       9.5   .6                                        acetate                                                                       isoamyl    1.77    2.0        .87   .4                                        acetate                                                                       amyl       74.6    41.8       30.8  .7                                        alcohols                                                                      isobutyl   31.6    19.2       13.6  .7                                        alcohol                                                                       propanol   45.8    31.7       9.9   .3                                        ethanol    5.2     4.36       0.54  .14                                       (vol %)                                                                       ______________________________________                                    

EXAMPLE 6

Michelob Pale Ale®, a specialty beer (feed solution) was contacted withcommercial grade O'Doul's® brew (pick-up fluid) through aPBG-4800/Celgard® 2500 liquid polymer membrane, prepared as describedabove.

Extraction was performed in batch mode for a period of 24 hours at roomtemperature, using a normal size laboratory scale extraction cellequipped with magnetic stirring. Table 8 shows the concentrations, inppm, of the flavor components found in the initial Michelob Pale Ale®and in the resulting pick-up fluid (hereinafter referred to as the"flavored pick-up" or the "enhanced flavor O'Doul's® brew"). Theenhanced flavor O'Doul's® brew contains 4-7 times the concentration ofhigher alcohols and over 20 times the concentration of esters than theoriginal O'Doul's® brew. Moreover, the enhanced flavor O'Doul's® brewhas a flavor component composition very similar to regular beer, such asBudweiser®, but has a significantly lower concentration of ethanol.

                  TABLE 8                                                         ______________________________________                                                  Initial   Initial   Final   Bud-                                              Pale Ale ®                                                                          O'Doul's ®                                                                          O'Doul's ®                                                                        weiser ®                            Component (ppm)     (ppm)     (ppm)   (ppm)                                   ______________________________________                                        ethyl acetate                                                                           44.0      0.7       17.0    23.0                                    isoamyl   3.2       0.1       2.2     2.1                                     acetate                                                                       amyl alcohols                                                                           78.0      8.6       39.0    71.0                                    isobutyl  34.0      1.4       10.0    10.0                                    alcohol                                                                       propanol  38.0      1.3       7.0     14.0                                    ethanol*  5.2       0.38      0.76    5.1                                     ______________________________________                                         *Ethanol concentration is % by volume.                                   

EXAMPLE 7

The process of Example 6 was repeated, except that the extraction wasperformed for a period of 21 hours at 4° C., using a 10× size laboratoryscale extraction cell, equipped with magnetic stirring. Table 9 showsthe concentrations, in ppm, of the flavor components found in theinitial Michelob Pale Ale® and in the resulting enhanced flavorO'Doul's® brew. The enhanced flavor O'Doul's® brew contains 2-3 timesthe concentration of higher alcohols and 16-20 times the concentrationof esters than the original O'Doul's® brew.

                  TABLE 9                                                         ______________________________________                                                  Initial   Initial   Final   Bud-                                              Pale Ale ®                                                                          O'Doul's ®                                                                          O'Doul's ®                                                                        weiser ®                            Component (ppm)     (ppm)     (ppm)   (ppm)                                   ______________________________________                                        ethyl acetate                                                                           44.0      0.7       15.0    23.0                                    isoamyl   3.2       0.1       1.6     2.1                                     acetate                                                                       amyl alcohols                                                                           78.0      8.6       24.0    71.0                                    isobutyl  34.0      1.4       24.0    71.0                                    alcohol                                                                       propanol  38.0      1.3       2.9     14.0                                    ethanol*  5.2       0.38      0.5     5.1                                     ______________________________________                                         *Ethanol concentration is % by volume.                                   

EXAMPLE 8

Miller High Life® (MHL), a beer having the alcohol and flavor componentsof a regular U.S. commercial beer (feed solution), was contacted withHPLC grade water (pick-up fluid) through a PBG-4800/Celgard® 2500 liquidpolymer membrane, prepared as described above. Extraction was performedin batch mode for a period of 24 hours at room temperature, using anormal size laboratory scale extraction cell equipped with magneticstirring. Table 10 shows the concentrations, in ppm, of the flavorcomponents found in the initial Miller High Life® and in the resultingpick-up fluid.

                  TABLE 10                                                        ______________________________________                                                  MHL     MHL        Final Final                                                (Initial                                                                              (Final     Pickup                                                                              Pick-up/                                             Feed,   Feed,      Solution                                                                            Feed                                       Component ppm)    ppm)       (ppm) Ratio                                      ______________________________________                                        ethyl     41.2    17.3       10.5  .61                                        acetate                                                                       isoamyl   2.7     1.2        0.8   .67                                        acetate                                                                       amyl      79      42.9       20.9  .49                                        alcohols                                                                      isobutyl  20      13.5       3.6   .27                                        alcohol                                                                       propanol  24      13.3       1.1   0.08                                       ethanol   4.43    4.36       0.19  0.04                                       (vol %)                                                                       ______________________________________                                    

EXAMPLE 9

Michelob Pale Ale®, a specialty beer (feed solution) was contacted withHPLC grade water (pick-up fluid) through a polydimethylsiloxaneelastomer membrane (MEM-100, Membrane products Corp., Utah), anun-coated solid siloxane elastomer flat sheet membrane, supplied in8.5×11 inch sheets, 3 mil (75 micron) thick). This sheet was cut toobtain a standard size sheet to fit the normal size extraction cell,having a membrane surface area of 8 cm². Extraction was performed inbatch mode for a period of 24 hours at room temperature, using a normalsize laboratory scale extraction cell equipped with magnetic stirring.Table 11 shows the concentrations, in ppm, of the flavor componentsfound in the initial Michelob Pale Ale® and in the resulting pick-upfluid.

                  TABLE 11                                                        ______________________________________                                                   Pale    Pale                                                                  Ale ®                                                                             Ale ®  Final Final                                                (Initial                                                                              (Final     Pickup                                                                              Pick-up/                                             Feed,   Feed,      Solution                                                                            Feed                                      Component  pm)     ppm)       (ppm) Ratio                                     ______________________________________                                        ethyl      47.9    17.6       15.8  0.90                                      acetate                                                                       isoamyl    3.8     0.73       0.80  1.1                                       acetate                                                                       amyl       89.0    45.2       37.8  0.84                                      alcohols                                                                      isobutyl   38.9    22.9       15.0  0.66                                      alcohol                                                                       propanol   52.3    36.4       11.1  0.30                                      ethanol    5.2     4.05       0.68  0.17                                      (vol %)                                                                       ______________________________________                                    

EXAMPLE 10

Michelob Pale Ale®, a specialty beer (feed solution) was contacted withcommercial O'Doul's® beer (pick-up fluid) in a hollow fiber module. Thisconfiguration provides for exposure or contact between the feed solutionand the pick-up fluid by circulating the feed solution through thelumens of hollow fibers having microporous walls supported in a housing,the fiber walls constituting the liquid polymer membrane, andcirculating the pick-up fluid over the outside of the fibers. Thisconfiguration provides very high surface area contact between the feedsolution and the pick-up fluid. The supported liquid polymeric membrane,used herein, was prepared by pouring heated (60° C.) polybutylene glycol(Mol. Wt. 4800) into the lumen side of a vertically oriented Liqui-Cel®Extra-Flow Membrane Contactor module (Hoechst Celanese Corp., Charlotte,N.C.). The polymer was allowed to drip out by gravity overnight.Nitrogen was then passed through the lumen side for 2 hours to force outthe residual polymer. The cell reservoirs, equipped with magneticstirrers, were connected to the hollow fiber module with Teflon flexibletubing. The tubing passed through a 4 inch diameter rubber stoppersealing the reservoirs.

Table 12 presents the results of the extraction, conducted for 24 hours,in batch mode and at 4° C., using approximately 2.1 liters each of thefeed and pick-up fluids. Membrane area in contact with the liquids was14,000 cm².

                  TABLE 12                                                        ______________________________________                                                Pale    Pale    Initial Final                                                            Ale ®TM.                                                                          O'Doul's ®                                                                       O'Doul's ®                                                                         Final                                               (Finaltial                                                                             (Initial                                                                                 (Final                                                                            Pick-up/                                       Feed,   Feed,    Pick-up,                                                                              Pick-up,                                                                              Feed                               Component                                                                                    ppm)                                                                             ppm)       ppm)                                                                                   ppm)                                                                                 Ratio                            ______________________________________                                         ethyl  23      9.8     --      10      1.0                                   acetate                                                                       isoamyl      2        0.5                                                                                     --                                                                                    0.6                                                                                 1.2                             acetate                                                                       amyl            101                                                                               54          7.5                                                                                   50                                                                                  0.93                            alcohols                                                                      isobutyl                                                                                   42      27         2.8                                                                                   15                                                                                  0.56                            alcohol                                                                       propanol                                                                                   41      29         2.1                                                                                   8.7                                                                                0.30                             ethanol      5.24                                                                                 4.3        0.51                                                                                  0.92                                                                                0.22                             (vol %)                                                                       ______________________________________                                    

EXAMPLE 11

O'Doul's® beer (commercial sample, feed solution), having a beanieoff-flavor, was contacted with carbonated water (feed solution), in acold room at a temperature of about 40 to 50 F, using a Liquid-CellExtra-Flow membrane module (available from Hoechst-Celanese Corp.,Charlotte, North Carolina) having a 4" diameter and length of 28",containing hollow fibers with a total membrane area of 19.2 m². Thesupported liquid membrane of the membrane module was prepared byimpregnating the hollow fiber membranes with polybutylene glycol (Mol.Wt. 4800). The feed solution, O'Doul's® low-alcohol brew (about 16liters), was pumped in a single pass continuously through the lumen sideof the module at a flowrate of 300 ml/min and the effluent collected ina stainless steel tank. The pick-up fluid, de-aerated water (about 16liters), was circulated through the shell side of the module at about 6liter/min. The resulting treated feed solution was pressurized to about20 psi with carbon dioxide (for carbonation before being bottled, cappedand pasteurized. A tasting panel found that the beanie note was nolonger present in the treated O'Doul's® and, as a result, this treatedbeer tasted significantly better than the original O'Doul's®.

EXAMPLE 12

Example 11, was repeated, except that the feed solution was pumpedthrough the shell side of the module at a flowrate of about 500 ml/min.Carbonated water was used as the pick-up fluid and was circulatedthrough the lumen side of the module at a rate of 3 liters/min. Atasting panel found no beanie note present in the treated O'Doul's®.

EXAMPLE 13

Example 12, was repeated, except that the feed solution was pumpedthrough the shell side of the module at a flowrate of about 1000 ml/min.Carbonated water was used as the pick-up fluid and was circulatedthrough the lumen side of the module at a rate of 3 liters/min. Atasting panel found the treated O'Doul's® produced according to thisprocedure to contain some residual beanie note.

Other variations or modifications, which will be obvious to thoseskilled in the art, are within the scope and teachings of thisinvention. This invention is not to be limited except as set forth inthe following claims.

We claim:
 1. A process for making an enhanced flavor low-alcohol brewhaving improved flavor comprising:contacting a full flavor beer feedsolution with a surface of hydrophobic membrane and contacting alow-alcohol brew pick-up fluid with an opposing surface of saidmembrane, and extracting desirable flavor components from said feedsolution into said pick-up fluid to form said enhanced flavorlow-alcohol brew, wherein, after extraction, the low-alcohol brewpick-up fluid is said enhanced flavor low-alcohol brew.
 2. A process formaking an enhanced flavor low-alcohol brew having improved flavorcomprising:contacting a low-alcohol brew feed solution with a surface ofa hydrophobic membrane and contacting a carbonated water pick-up fluidwith an opposing surface of said membrane, and extracting undesirableflavor components from said feed solution into said pick-up fluid toform said enhanced flavor low-alcohol brew.
 3. A process according toclaims 1 or 2, wherein said hydrophobic membrane comprises a hydrophobicsolid membrane or a hydrophobic liquid membrane having a microporoussupport.
 4. A process according to claim 3, wherein said hydrophobicliquid membrane is a microporous solid support having a hydrophobicliquid oligomer or polymer immobilized therein and said hydrophobicliquid oligomer or polymer is a liquid selected from the groupconsisting of polyalkylene oxides, polyesters, polyureas, polyurethanes,silicone oils, paraffin oils and functionalized polyolefins.
 5. Aprocess according to claim 4, wherein said hydrophobic liquid oligomeror polymer is a polyalkylene oxide.
 6. A process according to claim 5,wherein said hydrophobic liquid oligomer or polymer is polypropyleneoxide or polybutylene oxide.
 7. A process according to claim 4, whereinsaid microporous support is comprised of a material selected from thegroup consisting of polyolefins, polysulfones, polytetrafluoroethylenes,polycarbonates, polyether ketones and polystyrenes.
 8. A processaccording to claim 7, wherein said microporous support is comprised of apolyolefin film.
 9. A process according to claim 8, wherein saidpolyolefin is polypropylene.
 10. A process according to claim 7, whereinsaid microporous support is comprised of a hollow polyolefin fiber. 11.A process according to claim 10, wherein said polyolefin ispolypropylene.
 12. A process according to claim 3, wherein saidhydrophobic liquid membrane comprises a hydrophobic polypropylene glycolor polybutylene glycol oligomeric or polymeric liquid immobilized withina microporous polypropylene support.
 13. A process according to claim 3,wherein said hydrophobic solid membrane comprises a solid polymerselected form the group consisting of polyalkylene oxides, polyesters,polyureas, silicones and polyurethanes.
 14. A process according to claim13, wherein said solid polymer is a continuous film, is polymerized inor compressed into the pores of a microporous support, or is a thin filmformed on a support.
 15. A process according to claim 14, wherein saidmicroporous support is comprised of a material selected from the groupconsisting of polyolefins, polysulfones, polytetrafluoroethylenes,polycarbonates, polyether ketones and polystyrenes.
 16. A processaccording to claim 15, wherein said microporous support is comprised ofa polyolefin film.
 17. A process according to claim 16, wherein saidpolyolefin is polypropylene.
 18. A process according to claim 16,wherein said low-alcohol enhanced flavor brew has an ethanol contentless than about 3.0% by volume.
 19. A recycle process for making anenhanced flavor fluid having improved flavor comprising:a) (i)contacting a first full flavor feed solution containing flavorcomponents with a surface of a hydrophobic membrane and contacting apick-up fluid containing less of said flavor components with an opposingsurface of said hydrophobic membrane, and(ii) extracting flavorcomponents from said feed solution into said pick-up fluid to form saidenhanced flavor fluid and an extracted feed solution; b) treating saidextracted feed solution to remove or substantially remove an undesiredcomponent therefrom to form a treated extracted feed solution; c) (i)contacting a second full flavor feed solution containing flavorcomponents with a surface of a hydrophobic membrane and contacting asecond pick-up fluid, comprising said treated extracted feed solutionhaving an undesired component removed or substantially removedtherefrom, with an opposing surface of said hydrophobic membrane,and(ii) extracting flavor components from said feed solution into saidsecond pick-up fluid comprising said treated extracted feed solution toform an enhanced flavor fluid having an undesired component removed orsubstantially removed therefrom and an extracted feed solution; and d)repeating, in sequence, steps b and c.
 20. A process according to claim19, wherein said hydrophobic membrane comprises a hydrophobic solidmembrane or a hydrophobic liquid membrane having a microporous support.21. A recycle process for making an enhanced flavor low-alcohol brewhaving improved flavor comprising:a) (i) contacting a first full flavorbeer feed solution with a surface of a hydrophobic membrane andcontacting a low-alcohol brew pick-up fluid with an opposing surface ofsaid hydrophobic membrane, and(ii) extracting flavor components fromsaid feed solution into said low-alcohol brew pick-up fluid to formenhanced flavor low-alcohol brew and an extracted beer; b) treating saidextracted beer to remove or substantially remove ethanol to form alow-alcohol brew; c) (i) contacting a second full flavor beer feedsolution with a surface of said hydrophobic membrane and contacting asecond pick-up fluid, comprising said low-alcohol brew pick-up fluid ofstep b), with an opposing surface of said hydrophobic membrane, and(ii)extracting flavor components from said second beer feed solution intosaid low-alcohol brew of step b) to form enhanced flavor low-alcoholbrew and an extracted beer; and d) repeating, in sequence, steps b andc.
 22. A process according to claim 21, wherein said hydrophobicmembrane comprises a hydrophobic solid membrane or a hydrophobic liquidmembrane having a microporous support.
 23. A process according to claim22, wherein said hydrophobic membrane is a microporous support having ahydrophobic liquid oligomer or polymer immobilized therein and saidliquid oligomer or polymer is a liquid selected from the groupconsisting of polyalkylene oxides, polyesters, polyureas, polyurethanes,silicones and functionalized polyolefins.
 24. A process according toclaim 23, wherein said hydrophobic liquid oligomer or polymer ispolypropylene oxide or polybutylene oxide.
 25. A process according toclaim 22, wherein said microporous support is comprised of a materialselected from the group consisting of polyolefins, polysulfones,polytetrafluoroethylenes, polycarbonates, polyether ketones andpolystyrenes.
 26. A process according to claim 25, wherein saidmicroporous support is comprised of a polyolefin film or a hollowpolyolefin fiber.
 27. A process according to claim 26, wherein saidpolyolefin is polypropylene.
 28. A process according to claim 22,wherein said supported polymeric hydrophobic liquid membrane comprises ahydrophobic polypropylene glycol or polybutylene glycol oligomeric orpolymeric liquid immobilized within a microporous polypropylene support.29. A recycle process for making an enhanced flavor low-alcohol brewhaving improved flavor comprising:a) (i) contacting a first full flavorbeer feed solution with a surface of a supported polymeric hydrophobicliquid membrane and contacting a low-alcohol brew pick-up fluid with anopposing surface of said liquid membrane, and(ii) extracting flavorcomponents from said feed solution into said low-alcohol brew pick-upfluid to form enhanced flavor low-alcohol brew and an extracted beer; b)treating said extracted beer to remove or substantially remove ethanolto form a low-alcohol brew; c) (i) contacting a second full flavor beerfeed solution with a surface of a supported polymeric hydrophobic liquidmembrane and contacting a second pick-up fluid, comprising saidlow-alcohol brew pick-up fluid of step b), with an opposing surface ofsaid liquid membrane, and(ii) extracting flavor components from saidsecond feed solution into said low-alcohol brew of step b) to formenhanced flavor low-alcohol brew and an extracted beer; and d)repeating, in sequence, steps b and c, wherein said supported polymerichydrophobic liquid membrane comprises a microporous support having ahydrophobic liquid oligomer or polymer immobilized therein.